Recent research findings suggest that hormone/estrogen replacement therapy may reduce the risk of cognitive decline (particularly memory functioning) in a number of age-associated conditions, such as Alzheimer's disease, Parkinson's disease, and in otherwise healthy postmenopausal women but results have been equivocal. Variability in memory functioning may be in part related to the differential distribution of estrogen receptors throughout the brain and relatedly the differential effect of ovarian hormones on various memory subsystems. Thus, memory functions subserved by brain regions with higher ovarian hormone concentrations (e.g., prefrontal lobe), may be affected differentially by a decline in gonadal steroid hormones relative to memory functions subserved by brain regions with lower ovarian hormone concentrations (e.g., medial temporal lobe), although the mechanism underlying this differential influence is not known. The effects of ovarian hormones on memory subsystems may be elucidated by comprehensively assessing memory function in young, premenopausal women in a pharmacologic induced hypogonadal state. The proposed study will investigate the effects of a 3-month intervention period of leuprolide acetate on cognitive function and mood to accomplish the following specific aims: [unreadable] 1. To determine whether women receiving leuprolide acetate demonstrate a decline on a [unreadable] neuropsychological battery assessing episodic memory after 3 months of treatment. [unreadable] 2. To determine whether women receiving leuprolide acetate demonstrate a differential pattern of performance after 3 months on memory tasks mediated by the prefrontal lobe (e.g., strategic/working memory, such as list learning) versus those mediated by the medial temporal lobe (e.g., associative memory, such as recall of prose passage). [unreadable] 3. To determine whether women receiving leuprolide acetate demonstrate a differential pattern of performance after 3 months on sexually dimorphic tasks, such as verbal fluency and visuospatial abilities. [unreadable] 4. To determine whether possible fluctuations in mood status may underlie any observed changes in the above cognitive abilities. [unreadable] [unreadable] [unreadable]